1. Field of the Invention
The present invention relates to a printer device which includes image formation means, a lower body and an upper body which is shifted upward with respect to the lower body so as to be opened, and more particularly, to a tandem-type color printer device including a plurality of image formation units which are detachable from and attachable to the printer device.
2. Description of the Related Art
Conventionally, a well-known printer device includes at least one image formation unit which is detachable from and attachable to the printer device, a lower body and an upper body which is lifted upward with respect to the lower body for the maintenance sake.
FIG. 21 shows an outside perspective view of a conventional monochrome printer device (image formation device). In the illustration, a printer device 1 comprises a roof 2, which forms an upper body, and a lower body 3. The roof 2 includes a paper outputting section 5 from which a paper is output onto the roof 2, and a paper outputting tray 6 for outputting papers one on top of another. The lower body 3 includes a front cover 7 which can be opened and closed in the front section of the lower body 2, and a paper cassette 8 which is detachable from and attachable to the lower body 3. An MPF (Multi Paper Feeder) tray 9 which can be contained in the lower body 3 is arranged on the right side of the printer device 1. An operational display section 4 for inputting information to the printer device 1 or for displaying the state of printer device 1 is arranged on the right upper side of the printer device 1.
In such a printer device 1, the roof 2 is opened in a direction shown with an arrow B centrically at a rotational axis A, when clearing a jam occurring in the printer device or carrying out a maintenance operation. FIG. 22 shows a cross sectional view of the printer device together with the internal structure thereof. As illustrated in FIG. 22, the printer device 1 comprises: a paper cassette 8 which is detachable from and attachable to the printer device 1; a paper feeding roller 12 which sequentially feeds papers contained in the paper cassette 8; a pair of suspension rollers 13 which suspend a received paper and send the paper to an image formation section 11 at a predetermined timing, in association with a pair of paper outputting rollers 18; a fixation unit 14 which fixes a toner image onto a paper; the pair of paper outputting rollers 18 (a driving roller 18a and a driven roller 18b) which output the paper onto which the toner image is fixed; and an operational display section 4 for performing various settings for the printer device 1 or displaying the state of the printer device 1.
In the image formation section 11, a charger 25 uniformly charges electric charges onto the circumferential surface of a photosensitive drum 23. A printing head 26 selectively exposes the circumferential surface of the photosensitive drum 23 based on printing data The electric potential of a portion of the photosensitive drum 23, whose circumferential surface is exposed, is lower than that which is charged with electricity. Hence, an electrostatic latent image is formed on the circumferential surface of the photosensitive drum 23. A developing unit 27 transfers internally contained toner onto the low potential section of the photosensitive drum 23 through a developing roller 27a so as to develop the electrostatic latent image. A transfer unit 28 transfers the toner image on the photosensitive drum 23 onto a paper to be conveyed, with an electric field whose polarity is opposite to that of the toner.
The photosensitive drum 23, the charger 25, the developing unit 27, the transfer unit 28, a cleaner 24, etc. which are included in the image formation section 11 are included in the lower body 3, while the printing head 26 is arranged on the roof 2 as the upper body.
The roof 2 can be opened and closed centrically about a hinge section 15 in both directions as shown with arrows B and Bxe2x80x2. At this time, the printing head 26 and the driven roller 18b are incorporated with the roof 2 so as to be opened and closed altogether. The roof 2 shown with a straight line in FIG. 22 is in the state where it is closed, while the roof 2 shown with a broken line is in the state where it is opened. To keep the roof 2 opened, a body locking mechanism 16 is arranged. The body locking mechanism 16 is composed of a hook 17a arranged on the lower body 3 and an engagement section 17b which is arranged on the roof 2 and engaged with the hook 17a. 
The image formation section 11 mainly forms a cartridge CT as an image formation unit which is detachable from and attachable to the lower body 3. The cartridge CT includes the first cartridge CT1 comprising the photosensitive drum 23 and the cleaner 24, etc, and the second cartridge CT2 including the developing unit 27. The cartridge CT is dividable into the cartridges CT1 and CT2. In the state where the roof 2 is opened, the cartridges CT1 and CT2 can be detached from and attached to a predetermined installation section of the lower body 3. If a photosensitive drum 23 is deteriorated or if toner ran out, for example, the cartridge CT1 or CT2 can be replaced with a new cartridge, or other expendable supplies can be provided as needed, thus achieving the machine maintenance operation of the printer device.
In recent years, color printer devices (color image formation devices) are widely used, and various color printing methods are employed. For example, according to one technique, a plurality of developing units are arranged adjacent to the circumferential surface of one photosensitive drum, and toner images are sequentially formed on the surface of the drum (technique (I)). There is another technique (II), which employs an intermediate transcription medium in a drum-like form. A plurality of image formation units are arranged in a predetermined direction, and toner images are sequentially output on one top of another on a paper so as to form an image (what is so-called a tandem-type printing technique).
In the above technique (I), it is necessary to use a large-sized photosensitive drum, and it is difficult to form an image formation section in one unit, resulting in low printing performance. In the above technique (II), because the intermediate transcription medium is used, the size of the printer device itself is formed large.
It is demanded that tandem-type color printer devices with an excellent shape can perform high-speed printing. In this type of printer device, image formation units of, for example, yellow (Y), magenta (M), cyan (C), and black (K) are used. Such image formation units are articles of consumption which are to be used up, thus need to be replaced with new ones periodically.
In the printer devices having the structure shown in FIGS. 21 and 22, the image formation unit is formed in the lower body 3. If the structure is employed in a tandem-type color printer device, the image formation units of yellow (Y), magenta (M), cyan (C), black (K) are sequentially arranged in the lower body 3. Hence, in the case of a maintenance operation, after the roof 2 is once opened, each of the image formation units needs to be taken out upward.
In the above-described conventional image formation device, even when only the first cartridge CT1 (note: the first cartridge CT1 lasts for a different time period from that of the second cartridge CT2) forming the image formation unit (cartridge CT), the cartridge CT (in the state where the cartridges CT1 and CT2 are incorporated together) is taken out from the printer device. The cartridge CT is divided into the cartridges CT1 and CT2. Then, a new cartridge CT1 is incorporated with the cartridge CT2, thereby forming a new cartridge CT. After this, the cartridge CT needs to be installed in the printer device.
Especially, in a tandem-type color printer device, toners of, for example, yellow (Y), magenta (M), cyan (C), black (K) are used. Cartridges CT1 and CT2 are necessarily prepared for each of the colors, thus requiring frequent operations for replacing the cartridges CT1 and CT2 with new cartridges. In addition, in the conventional printer devices, the cartridges CT1 and CT2 are taken out upward as described above, and new cartridges CT1 and CT2 are set in predetermined positions in the printer device.
Since the cartridges CT1 and CT2 are detachable from and attached to the lower body 3, the cartridges CT1 and CT2 are once taken out, when to carry out a process for clearing a paper jamming occurring in a paper conveyer path formed underneath the cartridges CT1 and CT2. When the upper body is opened, if a paper jamming occurs somewhere quite far from a rotational axis A, the jamming is easily cleared because the upper body and the lower body are sufficiently separated at a distance. On the contrary, if a paper jamming occurs somewhere adjacent to the rotational axis A, it is difficult to clear the jamming because the upper and lower bodies are not sufficiently separated.
Under the consideration of the above problems, the cartridges may be arranged on the side of the upper body. In the conventional printer device, the roof 2 is opened centrically about the rotational axis A, in other words, the roof 2 is opened about one end thereof as a fulcrum. Hence, it would not have mattered so much for monochrome printer devices, but for tandem-type color printer devices, a mechanical deterioration occurs because of the heavy weight of the upper body. This causes positional deviations of the image formation units and difficulty in stabilizing printing performance. Because the upper body is opened about the one end thereof as a fulcrum, the image formation unit is so difficult to be detached from and attached to the printer device.
In tandem-type image formation devices, the plurality of image formation units are used as described above. Hence, when the image formation units are driven, they need to completely be locked. Besides, the locking of the image formation units needs to be improved as should be performed with ease.
Furthermore, in the above conventional printer device, the roof 2 rotates upward during the maintenance operation, the operational display section 4 can not be arranged on the roof 2 (if the operational display section 4 is arranged on the roof 2, the operator of the printer device can not reasonably see the display section), thus is arranged on the lower body 3. In this structure, therefore, the printer device can not freely be designed. Besides, the operational display section 4 projects as shown in FIG. 21, is an obstacle on the way to utilization of the printer device, and results in a large size of the printer device entirely.
The present invention has been made in consideration of the above. It is accordingly an object of the present invention to provide a printer device, which can realize high quality printing, includes a newly-designed link mechanism for shifting an upper body approximately in parallel with respect to a lower body, and a plurality of image formation units on the upper body, and can retain the maintenance operation without having any mechanical deterioration.
Another object thereof is to provide a printer device which includes cartridges sliding in both forward and backward directions so as to be detached from and attached to the printer device, and wherein each of image formation units can be replaced with new units easily.
Still another object thereof is to provide a printer device wherein a plurality of image formation units can synchronously be locked with an easy operation.
Yet still another object thereof is to provide a printer device wherein an operational display section can be seen even when an upper body is opened, and which is improved in machine operations.
In order to achieve the above objects, there is provided a printer device, which includes a paper conveyer path and image formation means for forming an image on a paper conveyed along the paper conveyer path, and is dividable into an upper body and a lower body, the printer device comprising
a body linking mechanism for opening the upper body with a predetermined interval between the lower body, and connecting the upper body and the lower body, and
wherein a posture of the upper body with respect to the lower body is retained, by the body linking mechanism, approximately same as a posture of the upper body which is closed, when opening the upper body upward with respect to the lower body, and the upper body is shifted in directions except in a forward direction.
In thus structured printer device according to the present invention, the printer device is divided into the upper body and lower body, by opening the upper body. The image formation means may include image formation units for colors of magenta (M), cyan (C), yellow (Y) and black (K) which are sequentially arranged in a predetermined direction. Each of the image formation units is formed of a drum unit including a charger, a photosensitive drum, etc., and a toner unit containing a developing roller, toner, etc. Each of the image formation units including the drum unit and the toner unit can be arranged on the upper body. If the upper body is shifted upward so as to be opened, the paper conveyer path is opened. In this structure, a process for clearing any jams occurring in the printer device can be carried out, and the drum unit or toner unit can be pulled out so as to be replaced with new one. That is, the maintenance operations of the printer device can be carried out easily. The drum and toner units for the above respective colors are set on the same upper body, thus improving the positioning accuracy in image printing with high quality printing performance.
In the printer device,
the body linking mechanism includes:
a pair of first arms each of which has a rotational fulcrum at a central section of either one side surface of the lower body;
a pair of second arms each of which has a rotational fulcrum at an outer section of either one side surface of the lower body; and
a pair of link members which are arranged on respective side surfaces of the upper body, and rotatively and oppositely connected to corresponding ones of the respective first and second arms.
According to the above structure, with the link mechanism, the upper body can be shifted upward approximately in parallel with respect to the lower body. In addition, the upper body can smoothly and stably be opened or closed. Besides, the upper body is shifted approximately in parallel with respect to the lower body, thus the operational display section can be arranged on the upper body, for example.
In the printer device, the body linking mechanism further includes:
a first and second rotational members each of which has a rotational fulcrum which coincides with the corresponding rotational fulcrum of the first and second arms, and which are rotated along with rotations of the first and second arms; and
driving transmission members which are arranged between the first and second rotational members and transmit, to the first and second rotational members, a driving force for forcing the first and second arms to rotate centrically at their rotational fulcrums.
The driving transmission member is a rotational transmission member, such as a belt or the like. According to this structure, the rotation between the first arm and the second arm is processed in association with the driving transmission member, and the upper body is smoothly shifted upward and downward.
In the printer device,
a length of the first arm is larger than a length of the second arm; and
a position of the rotational fulcrum of the first arm is higher than a position of the rotational fulcrum of the second arm.
According to this structure, the length of the first arm differs from the length of the second arm. Hence, the interval between the upper body and the lower body can appropriately be set, and the upper body lifted upward can be adjusted to have an appropriate distance from the lower body.
In the printer device,
the body linking mechanism includes a link member for linking the upper body with the lower body; and
the link member includes a damper which controls a rotational speed of the upper body, when the upper body is rotated so as to be closed, and which does not operate when the upper body is rotated so as to be opened.
According to this structure, when opening the upper body, the upper body can smoothly be opened while controlling a sudden fall of the upper body according to the law of gravitation. This prevents any shock in the printer device, secures the positioning accuracy in the image printing, and prevents breakdown of the printer device.
The printer device further includes
additional tension providing means for providing additional tension for forcing the upper body to be shifted upward with respect to the lower body in such a direction that the upper body is opened; and
body locking means for retaining the upper body in a position where the upper body is closed.
The additional tension forcing means is an elastic body such as a spring, etc. The body locking means is means fixed on the upper body, such as a hook, etc. According to this structure, the opening of the upper body can be achieved only with very light force, facilitating the machine maintenance operations.
In the printer device, the image formation means is formed of a plurality of members incorporated with each other, and includes at least one image formation unit, which is detachable from and attachable to the upper body. According to this structure, when the upper body is opened, the image formation unit is also lifted up. The image formation unit is pulled out so as to be easily detached from the upper body. Because the drum unit and the toner unit are formed independently, they can be replaced separately. It is especially be effective if the image formation unit is formed of a drum unit and a toner unit both having different periods of life.
In the printer device,
the image formation unit is formed of a drum unit, having a photosensitive drum, and a toner unit, having a developing roller;
the drum unit and the toner unit are formed at a predetermined interval in a state where the upper body is opened, and formed in such a way that the photosensitive drum and the developing roller are pressure-welded in a state where the upper body is closed.
According to this structure, the upper body can smoothly be opened and closed. The drum unit and the toner unit can be detached from and attached to the upper body which is shifted upward in parallel with respect to the lower body.
In the printer device according to the present invention, the image formation unit includes a plurality of image formation units arranged along the paper conveyer path, thereby to realize a tandem-type printer device. The plurality of image formation units are prepared for colors of magenta (M), cyan (C), yellow (Y) and black (K), and arranged in a sequential order.
In the printer device,
each of the plurality of image formation units includes a position determination shaft;
a plurality of shaft receivers, which are adjacent to the position determination shafts of the respective image formation units, are arranged in the lower body, when the upper body shifted back to the lower body so as to be closed; and
each of the plurality of shaft receivers has a shaft locking mechanism so as to be locked by an operation of a single lever.
According to this structure, the position determination axes are easily locked. When the upper body is shifted back toward the lower body, the image formation units are securely locked as well.
The shaft locking mechanism:
includes a rotator which rotates along with the operation of the lever, and a rotational member which changes a level of a rotational force of the rotator to a level of a driving force of the shaft receivers; and
drives the shaft receivers with the driving force changed by the rotational member, and controls the position determination shafts to lock the shaft receivers, respectively. According to this structure, the plurality of position determination axes are synchronously locked with the shaft locking mechanism by manipulating the lever.